Large motor drills, for example orbital drills, are used in the aircraft construction industry to drill holes in horizontal surfaces of aircraft components. Examples of such aircraft horizontal surfaces include upper wing surfaces, upper horizontal stabilizer surfaces, fuselage crown surfaces, floor surfaces, etc. The large motor drills used for drilling holes in the horizontal surfaces can weigh as much as 50 pounds (22.6 kilograms). An operator of the drill may lift the drill weight between each hole drilled. Operators are at times in a kneeling position when drilling these holes. The repetitive lifting of the drill by the operator of the drill may create ergonomic issues.
Counterbalance arms have been used to assist the operator of a large motor drill in lifting the drill. In the construction of a typical counterbalance arm, one end is connected to the drill and the opposite end is mounted to a hard structure of the aircraft assembly area, for example a structural frame member of an aircraft assembly building. However, the construction of an aircraft assembly building does not always support requirements for a counterbalance arm to be mounted to a structure of the building. Additionally, counterbalance arms are set up to enable the performance of a particular drilling operation, and then removed when the drilling operation is completed or a new drilling operation is to be performed. This adds to the cycle time of performing drilling operations on a particular component of an aircraft construction. Also, counterbalance arms may be relatively expensive. Furthermore, employing a counterbalance arm to assist in performing a particular drilling operation on a particular component of an aircraft construction can significantly increase the operating footprint, or the area of the aircraft where an operator is performing a drilling operation. This can negatively impact a particular drilling operation cycle time when multiple operators must work within a limited space or area of the aircraft being constructed.
Counterbalance reels have also been employed to support or suspend large motor drills above an area of an aircraft construction where a particular drilling operation is to take place. However, counterbalance reels require overhead support, for example an overhead structure of an aircraft assembly building to react the load or support the weight of the large motor drill. This may not be a viable option when performing drilling operations in upper horizontal surfaces of aircraft components. Additionally, like the counterbalance arms, counterbalance reels require additional set up time and tear down time, which negatively impacts the cycle time of performing a particular drilling operation.